Jupiter is an applet designed for netbooks and laptops that you can use to switch between maximum and high performance and power saving mode, change the resolution and orientation, enable or disable the bluetooth, touchpad, WiFi and so on. If you own an Asus EeePC netbook, there's also a separate package that adds support for Asus Super Hybrid Engine (SHE) as well as some other EeePC tweaks.

Jupiter doesn't work by default in Ubuntu 11.10 Oneiric Ocelot due to some Mono changes, but you can now use it thanks to a "hack" provided by WebUpd8 reader mtron. If you want to help getting Jupiter to work in Ubuntu 11.10 Oneiric Ocelot without this "hack", get the Jupiter source code from HERE.

Please note that because of a bug in Unity 2D, the Jupiter icon won't show up in the systray (it works just fine in Unity 3D though).

But, like I've said, you don't have to wait for this fix to get Jupiter working in Oneiric because I've applied mtron's tweak to the Jupiter packages available in the Jupiter WebUpd8 PPA.

If you own Asus EeePC netbook, also install jupiter-support-eee - required for SHE (Super Hybrid Engine):

sudo apt-get install jupiter-support-eee

I've tweaked Jupiter to whitelist itself (this has been available since Ubuntu Natty) for the Unity systray so if you run Unity, after starting Jupiter for the first time you'll have to log out and log back in to see its icon in the notification area (systray). That's of course not the case if you've whitelisted the whole systray.

Bonus: if you want to use monochrome icons for Jupiter (light/dark), get them from HERE. For Ubuntu 11.10, you'll have to resize the icons to 24x24px (use the "nautilus-image-converter" package for easily resizing all the icons with 2 clicks; yes, it work with Nautilus 3 too).

If you're not using Ubuntu, you can download Jupiter via SourceForge (.rpm files available). To get it working with the latest Mono, use "/usr/bin/mono --runtime=v4.0.30319 /usr/bin/jupiter.exe" to run it (the Mono runtime version may be different for your Linux distribution).

Update: I've tweaked the package and it should now work with Unity 2D as well as Xubuntu too (Oneiric Ocelot).

Many thanks to mtron for the tip on how to get Jupiter to work in Ubuntu Oneiric!